Céline Dion is celebrating her 51st birthday with a title she never expected.

“I’m in shock, actually. I never, never expected something like this,” she says of being tapped by L’Oréal Paris as the brand’s new global ambassador. Growing up, she says, “I never really felt confident beauty-wise.” The honor couldn’t have come at a better time in her life. These days, “I’ve never felt as beautiful, as strong, and I really think that the best is yet to come.”

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Opening up to PEOPLE in this week’s issue, Dion shares what all it has taken to make her feel this way, following the devastating loss of her husband of 21 years René Angélil in January 2016. The hardest part was comforting her sons René-Charles, 18, and 8-year-old twins Nelson and Eddy. “All the little things in life, and the big things, they have to make you stronger,” she says, “Otherwise, you don’t understand the meaning of life itself.”

Sofia Sanchez & Mauro Mongiello for L’Oréal Paris

For more on Celine Dion and how she’s rebuilding her life after tragedy, pick up this week’s issue of PEOPLE, on newsstands Friday.

“I love fashion,” says Dion who credits her stylists, including dancer and very close pal Pepe Muñoz, with helping her choose bold looks that are “reflecting how I feel inside.”

Philippe Blet/REX/Shutterstock

On the outside, she admits she may look a little slimmer, but that is part of another positive change she’s made. “Dancing has been in my DNA all of my life,” says Dion who once dreamed of becoming a ballerina and has recently taken up ballet dance with the help of Muñoz. “It’s a dream. And so hard!”

Though online critics have tried to call attention to her appearance, she’s not paying them any attention: “I do this four times a week,” Dion says of ballet practice. “People say, ‘She’s a lot thinner’ but I’m working hard. I like to move and [weight loss] comes with it.”

Denise Truscello for L’Oréal Paris

Besides, Dion says feeling good is where beauty really comes from. “This is about confidence,” she says of what teaming up with the brand means to her. Gearing up to help promote L’Oréal’s Hair Excellence color line as well as various cosmetic products, Dion says “beauty is within, but when you can reflect it in the mirror, you’re ready to hit the world.”